In recent years, the novel flat panel display (FPD) industry has developed with each passing day. Consumers' high requirements on large-size and high-resolution FPDs stimulate the entire industry to continuously improve the display technology. TFT backplane technology, which is regarded as the core technology of the FPD industry, also undergoes profound evolutions. Oxide TFT not only shows high migration but also shows simple manufacturing process, low production cost and superior large-area uniformity. Therefore, oxide TFT technology has attracted much industry attention since the birth.